In many modern applications, optical input/output (IO) is being used in computer systems to transmit data between system components. Optical I/O is able to attain higher system bandwidth with lower electromagnetic interference than conventional I/O methods.
U.S. Pat. No. 7,217,040 to Crews et al., commonly assigned with the present invention, discloses a blind mate optical connector including a floating component to receive a first set of optical waveguides, and a fixed component to receive a second set of optical waveguides and to facilitate optical alignment between the first set of waveguides and the second set of waveguides through automated alignments with the floating component.
Referring to FIG. 1 there is shown a block diagram of one embodiment of a computer system 100 which may benefit from such a connector. Computer system 100 is a blade server that includes a chassis 110 and blades 120. In one embodiment, blades 120 are “hot-swappable” devices that are coupled to a backplane of chassis 110. Each blade may be an independent server having one or more processors, an associated memory, disk storage and network controllers. Optical fibers are coupled to each of the one or more blades 120 at the backplane to facilitate optical I/O.
Blind-made optical connectors have existed for some time such as the so called multi-fiber push-on (MPO) connector. An drawback of using an MPO connector in the backplane application may be that the connector interface is very sensitive to dust. The interface relies on a butt-to-butt contact of two MT ferrules on each side to maintain optical communication.
If there is a 50 um diameter dust clogged between two MT ferrules, optical coupling loss can go up dramatically. Since dust is inevitable in general operation environment, this issue has prevented the wide adoption of MPO connectors.
Second, high precision MT ferrule with better than 5 um tolerance at the alignment pin/hole is required to achieve excellent optical coupling. Third, the physical contact between the alignment pin and hole might wear out and it will increase the optical coupling loss significantly. Additionally there is a complex latch mechanism. Because of the high selling cost and expensive maintenance of using this type of connector, the MPO connectors are only used in some very high-end routers where the connector density is the most important consideration.